Some 2,500 earthquakes in Oklahoma linked to fracking

The last five years have seen Oklahoma experience more than 2,500 earthquakes – the vast majority of which are being connected to the oil and gas exploration process of fracking.

Although past studies have also suggested Oklahoma’s earthquake
spike is related to fracking, this is the first time scientists
have pinned such numbers to the controversial procedure. Notably,
they found that fracking could also be responsible for
earthquakes occurring nearly 20 miles away from drilling and
waste deposit sites.

According to Scientific American, Oklahoma has seen more
than 230 earthquakes registering magnitudes of 3.0 or higher in
this year alone. Before 2008, the state only averaged one of
these earthquakes a year.

In a report published by the journal Science, researchers from Cornell University and the
University of Colorado found that roughly 20 percent of all the
earthquakes that occurred in the central and eastern United
States were caused by activity at just four fracking wells
situated near the town of Jones, Oklahoma.

“It really is unprecedented to have this many earthquakes
over a broad region like this,” study co-author Geoffrey
Abers said to the magazine. “Most big sequences of
earthquakes that we see are either a main shock and a lot of
aftershocks or it might be right at the middle of a volcano in a
volcanic system or geothermal system. So you might see little
swarms but nothing really this distributed and this
persistent.”

Although the new research highlights the connection between
fracking and seismic activity, it’s not the oil extraction
process itself that is to blame. In order to release underground
oil and gas, fracking involves the injection of highly
pressurized water, sand, and chemicals into layers of rock, but
it’s actually the next step that’s causing concern among
geologists.

After a well is fracked, the leftover wastewater is then injected
back into the ground and stored in deep wells, some of which are
placed along fault lines. This process is believed to alter the
stress levels on existing fault lines to the point where they
fail and cause earthquakes.

“We view the expanding Jones earthquake swarm as a response
to regionally increased pore pressure from fluids injected at the
(southeast Oklahoma City) wells,” the study reads, according
to the Los Angeles Times. When the pressure keeps
mounting, “critically stressed, optimally oriented faults are
expected to rupture first.”

Notably, researchers also suggested that activity at these types
of injection wells could induce earthquakes miles away from their
location.

“The important thing is that we are seeing earthquakes that
are much more widely distributed, much farther from wells and in
a lot of different directions,” Abers told Scientific
American. “Some of these earthquakes are as much as 20 miles
away from what seems to be the primary wells that are increasing
the pressure.”

The study did not make a definitive statement regarding the cause
of all these earthquakes, but it did conclude that wastewater
injection is “likely responsible” for the spike.
Verifying the source conclusively could help regulators determine
whether or not changes could alleviate some of the concern behind
the process, especially since some scientists believe the current
wave of relatively small quakes could lead to far bigger and more
destructive tremors.

“I think ultimately, as fluids propagate and cover a larger
space, the likelihood that it could find a larger fault and
generate larger seismic events goes up,” Western University
earth sciences professor Gail Atkinson said back in May,
according to ThinkProgress.

As RT reported previously, Oklahoma has already
experienced more than 500 earthquakes of any magnitude in 2014.
Studies in Texas have also shown increased seismic activity to be
related to fracking, while regulators in Colorado temporarily
halted the disposal of fracking wastewater
after research linked a recent quake to a local oil operation.